The UK's highest selling newspaper may be embarking on a giant cover up -- much to the delight of its critics -- and putting an end to a tradition opponents see as sexist and outdated.

The Sun's topless model on Page 3 has been a tradition since the 1970s. A photo of a bare-breasted young woman along with a corny caption was the newspaper's way of giving its largely male readers a break from the often depressing news of the day.

Page 3 quickly became part of The Sun's brand, making the transition from black and white photos to color, then onto the paper's website. Page 3 models often support The Sun's campaigning journalism and are taken on tours to meet serving military.

Nudity in newspapers is not the exclusive domain of The Sun. The press and advertising campaigns will often use flesh to draw in the eyeballs in parts of Europe.

But now The Sun's owner Rupert Murdoch -- in one tweet -- has raised the specter of a world without Page 3. Murdoch said: "@Kazipooh page three so last century! You maybe right, don't know but considering. Perhaps halfway house with glamorous fashionistas."

Murdoch later tempered this, saying it was the editor's call. But it was music to the ears of campaigners at "No More Page Three." The campaign was started by Lucy Holmes when she realized the day after Jessica Ennis won Olympic gold in the heptathlon for Great Britain last summer "the largest female image in The Sun was of a young woman showing her breasts."

A spokesperson for News International said: "In a YouGov survey commissioned last October almost two thirds of Sun readers voted to keep the Page 3 format and notably it has more than seven million readers daily of which 45 per cent are female. It remains the UK's biggest selling newspaper which means its formula -- brilliant journalism, entertainment, outstanding sports writing -- and Page 3, is working."

The YouGov survey also found readers of most of the other national papers were more likely to favor an end to the Sun's Page 3.

Meanwhile, the UK media landscape is changing after the Leveson Inquiry into phone hacking. Sun staffers have been arrested, its sister paper The News of the World was closed by Murdoch and codes of conduct are being imposed on the media. The emphasis is on ethics, and that might not sit well on Page 3.

As an MP, Clare Short tried to pass a law that would ban topless models in newspapers.

One anti-Page 3 campaigner, Laura Ashton, told CNN: "It's exploitative, it's from the 1970s, and the girls back then were very young they were putting in the newspaper. They're not much older now. But it really feels very outdated, that kind of sexism."

Others have tried before. Clare Short was a leading Labour Party MP when in 1986 she tried unsuccessfully to push through legislation that would have outlawed topless models in newspapers. In 2007, Short tried again, only for The Sun to launch a "Hands Off Our Page 3" campaign with models being driven by bus to pose outside to the former MP's home.

In the UK, topless and nude model magazines are largely restricted to the top shelves of stores where children can't reach them. Only a couple of newspapers containing nudity are put on bottom shelf.

Elsewhere in Europe, different standards apply in different markets with topless models used on advertising hoardings for everything from soap to sweaters.

Some of the UK's Page 3 models have used their exposure as launchpad for other careers. Sam Fox, perhaps the best-known of them, had a string of pop hits.

Linda Lusaardi made her name as a Page 3 model but now says it may be time for its end.

And Linda Lusardi, another pin-up of the 1980s, became an actress in long-running UK shows like "The Bill" and "Emmerdale."

But even Lusardi, voted by Sun readers in 2005 as the best Page 3 girl ever, said: "It's time for it to go. I really think things have moved on so far with the internet and with everything else that I don't feel that we really need that in our national newspapers anymore."